Imagine an object A having a relation with an object B. the link is from A to B. let's write it A --> B. But I aslo want the object B to be linked to the object A. B --> A . I've found a document, named « Business Modeler IDE Best Practices Guide » on the GTAC. at the page 233, they explain a bit how to do this. it's by implementing a getter for the relation. unfortunately i don't know where to implement this getter. and even how to do that.